This invention relates to devices for applying lengths of pressure sensitive adhesive coated tape to rectangular objects such as a box driven along a predetermined path past the device.
The art is replete with such devices, U.S. Pat. Nos. 3,915,786 and 3,954,550 being illustrative examples. Such devices are commonly used to seal rectangular boxes filled with merchandise driven past the device by a conveyor. Typically such devices include an application member such as a roller for supporting an end of the tape adhesive side out in a contact position at which the tape end will be contacted by a box. Upon such contact the tape end adheres to the box. Further movement of the box then pulls the tape from the device between the box and the application member which presses the tape against the contour of the box. Subsequently the applied length of tape is severed from the supply length of tape and means on the device engages the tape adjacent the newly severed end and moves it with the application member back to its contact position for contact by the next box on the conveyor.
Typically the application member is mounted at one end of an arm which has its other end pivotably mounted at one edge of the path for the boxes so that after the leading surface of the box contacts the tape on the member, the member will revolve about the pivot point of the arm to follow the contour of the box and press the tape sequentially against the leading surface of the box, around a leading edge of the box adjacent the pivot point for the arm defined by adjacent edge portions of two butted cover flaps of the box, and then over adjacent portions of the cover flaps longitudinally of the box to seal the cover flaps together. Because of the decrease in angle between the leading surface of the box and a line between the pivot point for the arm and the application member as the box moves along the path, however, the force applied by the leading surface of the box to move the application member across its leading surface will increase significantly as the application member approaches the edge of the box and can become sufficiently large just before the edge of the box passes the application member to push in the leading wall of the box under its two cover flaps, particularly for lightly constructed boxes. This can damage merchandise in the box, and even if it does not, it will produce a taped box in which the tape bridges several centimeters between the cover flaps of the box and a portion of the front surface of the box, which bridging is unsightly and potentially insecure.